clinical report - tokuyama · diffuse through the enamel to the surface of the dentin, causing...
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Protective Sealant for Treatment of Hypersensitive Dentin
Clinical ReportLearning about Dentin Hypersensitivity Potential of Tokuyama Shield Force Plus
Dr.Morioki FUJITANI, DDS, PhD, FICD
Associate Professor,
Department of Operative Dentistry
School of Dentistry
Aichi Gakuin University
Dr.Ko HINOURA, DDS, PhDHinoura Dental Office
Two old friends, a university professor and a dental practitioner, discuss dentalhypersensitivity, touching on topics ranging from underlying mechanisms to treatmentapproaches to the potential of Tokuyama Shield Force Plus, a new product.
Hypersensitivity, a modern lifestylerelated disease
Dr. Hinoura: In my clinical practice, I've noticed growing numbers of patients complaining abouthypersensitivity. What's your experience?
Dr. Fujitani: I feel the same; maybe because more people keep their teeth into old age. I think it's alsothe result of the 8020 movement associated with the Ministry of Health, Labour and Welfare "HealthyJapan 21" program. [laughs]
Dr. Hinoura: In earlier times, dentists used to extract teeth even when they were just slightly damaged.As a result, people didn't have the chance to develop hypersensitive areas on their teeth. There's no doubtthe desire to keep our teeth is growing.
Dr. Fujitani: People who keep their teeth tend to be highly healthconscious. Nowadays, many peopleprefer foods they believe are healthy, like black vinegar. Substances like this often can cause acid erosionand sometimes lead to hypersensitivity. I think hypersensitivity due to acid erosion is an especially recenttrend. In contrast, we find attrition and abrasion going back as far as the Egyptian mummies. So, we mightsay hypersensitivity is a lifestylerelated disease characteristic of an aging or healthy society.
What mechanisms underlie hypersensitivity?
Dr. Hinoura: Surprisingly few people seem to understand the mechanisms underlying hypersensitivity.Would you care to give a brief explanation?
Dr. Fujitani: Before discussing the mechanisms underlying hypersensitivity, let me discuss the boundarybetween the diagnoses of hypersensitivity and pulpitis. The currently accepted textbook definition of theboundary goes as follows: pain that subsides in no more than 30 seconds after a stimulus generates pain ishypersensitivity; pain that lasts longer is pulpitis. But 30 seconds is a long time. Myself, I use 5 seconds asa guide. I diagnose pain subsiding within 5 seconds (transient) as hypersensitivity. A transient pain is like"ouch!" This condition activates the Aδfiber. Lingering pain"ouuuuch"generally activates Cfibers. I thinkmost patients who complain about hypersensitivity are experiencing pulpitis, which involves Cfiber spikes.
Dr. Hinoura: Obviously, an accurate diagnosis is essential before treatment. A diagnosis in terms of theduration of the pain is crucial.
Dr. Fujitani: Now we come to the mechanisms underlying hypersensitivity. Of the various current theories,the leading theory is the hydrodynamic theory: The motion of the dentinal fluid in the dentinal tubulesstimulates odontoblasts or nerve endings, which we sense as pain. Normally, the orifices of the dentinaltubules are closed, so the dentinal fluid doesn't move in response to external stimulation. But if the orificesare open for some reason (Table 1), cold water, a tooth brush, or the differences in osmotic pressuregenerated by sticky chocolate or bean paste can generate dentinal fluid movement. This is said to be themechanism underlying hypersensitivity (Figure 1).
[1]Periodontaltreatment
Excessive scaling and root planing.Periodontal treatment exposes dentin at root surfaces previously protected byperiodontal tissue, leaving dentinal tubules open and exposed.
[2] Homecare
Inappropriate brushing can lead to problems like gingival recession and wedgeshapeddefects.
[3]Occlusion
Occlusal trauma, excessive bruxism, and clenching cause problems. Caused byocclusion, wedgeshaped defects known as abfractions also raise various issues.
[4]Restorativeprocedures
Hypersensitivity often follows cavity preparations for a vital tooth or abutment toothpreparations. Preparing a molar typically exposes one to two million dentinal tubules.
[5]Orthodontictreatment
When force is applied to the tooth outward toward the lips (or the cheeks), gingivalrecession may occur in association with absorption of the alveolar bone.
[6]Whitening
When hydrogen peroxide is applied to the enamel surface, free radicals form anddiffuse through the enamel to the surface of the dentin, causing hypersensitivity.
Table 1: Causes of Dentin Hypersensitivity
Figure 1: Mechanism of Dentin HypersensitivityThe motion of the dentinal fluid stimulates nerve fibers. This isbelieved to cause dentin hypersensitivity (hydrodynamic theory).
How is hypersensitivity treated?
Dr. Hinoura: When we understand the mechanisms underlying hypersensitivity, we start to see how wecan treat it.
Dr. Fujitani: Right. As I said earlier, hypersensitivity is caused by nerve stimulation caused by movingdentinal fluid when the orifices of dentinal tubules are open. So we can divide treatment into three generalapproaches: closing the open dentinal tubules; getting the dentin fluid to coagulate; or raising thesensitivity threshold of the nerves themselves.
Dr. Hinoura: Many drug companies provide various products based on these treatment approaches.
Dr. Fujitani: For example, some drugs induce reactions between oxalic acid and the calcium in the toothsubstance to seal the orifices of the dentinal tubules (Figure 2). It's like sandbagging a river bank. Othersblock the orifices of the dentinal tubules with resinrelated or glassionomerrelated materials. That's likesealing a gap. Others use glutaraldehyde or HEMA to coagulate the dentinal fluid (Figure 3). Lasers alsocoagulate dentinal fluid. Other treatments use potassium ions to raise nerve sensory thresholds (Figure 4).
Figure 2: Suppresses dentinhypersensitivity by sealing opendentinal tubules.
Figure 3: Suppresses dentinhypersensitivity by causing fluid indentinal tubules to coagulate.
Figure 4: Suppresses dentinhypersensitivity by raising thethreshold of nerve fibers.
Dr. Hinoura: Effective treatment depends on an accurate diagnosis based on an understanding of themechanisms underlying hypersensitivity. Each product may or may not be effective, depending on thespecific case.
Dr. Fujitani: We, as dentists, are responsible for providing an accurate diagnosis and using appropriatematerials.
Dr. Hinoura: Ideally, we use these products as a last resort when symptoms don't improve, despitelifestyle modifications and efforts to activate our natural healing capacity, including remineralization. Still,patients who experience hypersensitivity also experience considerable discomfort, so we have to treat thepain first. One approach is to treat the pain first, then proceed to medical intervention.
Dr. Fujitani: I agree. That's why we need sufficient information for an accurate diagnosis.
A new desensitizing material
Dr. Hinoura: What do you think of Tokuyama Shield Force Plus, the new desensitizing material fromTokuyama Dental?
Dr. Fujitani: It's an innovation, the first resin desensitizing material covered by the Japanese healthinsurance system.
Dr. Hinoura: No previous resin desensitizing product has been covered by Japanese health insurance.
Dr. Fujitani: You use it yourself. What's your opinion?
Dr. Hinoura: The most striking feature is that it works immediately (Photograph 1a, b, Figure 5). Thespeed is amazing. It's highly adhesive and works wonders, sealing open dentinal tubules instantly. Ibelieve this is because it uses 3D SR monomer, a proprietary Tokuyama Dental technology used in theirbonding materials (Figure 6). We can repair actual physical defects in the tooth with composite resin, buthypersensitivity generally isn't accompanied by actual defects.
Photograph 1a: SEM image of open dentinal tubules (dentinhypersensitivity model). Stimulation readilyinduces dentinal fluid motion in dentinaltubules.
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Photograph 1b: SEM image after treatment with ShieldForce Plus.The image clearly shows complete sealingof previously open dentinal tubules.
Figure 5: Schematic illustration of ShieldForce PlusShield Force Plus forms resin tags in thedentinal tubules and seals the surface witha strong coating.
Figure 6: 3D SR monomerPhosphoric acid monomers form astructure similar to those of polyfunctionalmonomers, interacting with calcium in thetooth substance to seal dentinal tubuleorifices.
Dr. Fujitani: How long do the effects last?
Dr. Hinoura: Tokuyama Shield Force Plus seems to be fairly resistant to toothbrush abrasion, so we canexpect the effect to last for some time.
Dr. Fujitani: This Tokuyama Shield Force Plus treats a surprisingly wide range of symptoms. Obviously, itcovers cases attributable to the Aδfiber activation discussed before. It also covers cases associated withCfiber activation. We can also expect it to treat pulpitis in the early stages.
Dr. Hinoura: It's great for both patients and dentists.
Precautions for using Tokuyama Shield Force Plus
Dr. Fujitani: Are there any precautions for using Tokuyama Shield Force Plus?
Dr. Hinoura: Cleaning the tooth surface is important. Obviously, this requirement doesn't apply toTokuyama Shield Force Plus alone (Photographs 2, 3, 4, 5, 6, and 7).
Photograph 2: Thoroughly clean the tooth surface.In cases of severe pain, wipe the surfacewith cotton balls.
Photograph 3: If saliva remains on the tooth surface aftersurface cleaning, wipe the surface withcotton balls.
Photograph 4: Apply Shield Force Plus to the affected areawhile avoiding the gums. Allow to stand for10 seconds.
Photograph 5: Dry Shield Force Plus with gentle, thenmoderate, then forceful air drying. ShieldForce Plus seals dentinal tubules themoment it's applied, relieving pain.
Photograph 6: Expose the surface to light for at least 10seconds.
Photograph 7: After treatment: The coated surface blendsin with the rest of the dental surface.
Photograph 8: Apply Shield Force Plus with a flat brush.
Photograph 9: A liquid pool forms on the tooth surface (in
the gingival sulcus).Curing the resin in this state will result inburrs.
Photograph 10: Wipe off excess liquid with a flat brush.This will form a uniform layer and preventburr formation.
Photograph 11: Tooth surface (gingival sulcus) afterremoval of excess liquid with a flat brush.The layer is uniform.
Dr. Fujitani: But patients with hypersensitivity often won't let us touch the affected areas because of thepain. What do you do in these cases?
Dr. Hinoura: At the very least, you need to wipe the surface with cotton balls. Ideally, we'd remove all ofthe plaque. But if that's not possible, wiping the surface still helps. If the patient won't let us even wipe thesurface, we can't expect Tokuyama Shield Force Plus to help all that much, since such cases are clearly onthe brink of requiring pulp extirpation. Also important is applying an even coat.
Dr. Fujitani: I use a flat brush. This is effective in certain cases, for example, when I want to blow air afterapplying Tokuyama Shield Force Plus but can't, due to pain because the tooth is especially hypersensitive.Such is often the case with patients with dental hypersensitivity. Without air blowing, excess liquid mayresult in pooling in the gingival sulcus, and light irradiation in this state will result in burrs. To keep thisfrom happening, I use a flat brush to remove the excess liquid. I'd prefer to blow air to dry the solvent, butwhen I treat a patient who can't tolerate this, I remove the excess liquid with a flat brush. Allowing it standfor a while provides effects close to those achieved with blown air (Photographs 8, 9, 10, and 11).
Dr. Hinoura: Tokuyama Shield Force Plus seals the orifices of dentinal tubules the moment it's applied.This means patients who can't tolerate air blowing before the coating is applied sometimes don't mind itafter the coating is applied.
Dr. Fujitani: This is one aspect of what Tokuyama Dental calls the "doubleblocking" effect.
Dr. Hinoura: Right! But some patients can't tolerate the air blowing even after the coating is applied. Asyou said, using a flat brush often works in these cases.
Dr. Fujitani: If air blowing isn't possible, wipe the surface with a flat brush. It's something I'd recommendto all dentists.
Dr. Hinoura: Adequate irradiation with light is essential. This produces a stronger coat.
Dr. Fujitani: Light irradiation completes the doubleblock.
Potential of Tokuyama Shield Force Plus
Dr. Hinoura: I think the main advantage of Tokuyama Shield Force Plus is the immediacy of its effects.Hypersensitivity we couldn't do anything about in the past subsides instantly. It's appealing!
Dr. Fujitani: I agree. It helps gain the trust of our patients. They think, "Wow, he's a brilliant dentist!"These patients bring more patients.
Dr. Hinoura: All in all, dentists have to win the trust of their patients. It's important to be able to treat painimmediately. And, as a dentist, I have to say it's a delight to have more treatment options for my practice.
Dr. Fujitani: Tokuyama Shield Force Plus is powerful enough as a tool to attract potential patients. It cureshypersensitivity instantly and helps build patient confidence in their dentists. It's a winwin relationship.[laughs]
TOKUYAMA SHIELD FORCE PLUS
Protective Sealant for Treatment of Hypersensitive Dentin